I’m looking at putting plate steel inside the walls of a bus that I am converting, and I was wondering how thick of steel I should put in there for effective armor from rifle fire up to something like .30-06. Can you provide any guidance in this area? Thank you – T.K.
Hugh Responds: If you are talking mild steel plates, there isn’t any thickness that I would recommend. Mild steel (the most common plate steel) is so soft that thicknesses of greater than 1” may be required. Many today use abrasion resistance steel (steel intended for large earth moving equipment) with AR500 being the most common, but it is still less than optimal. 3/8” seems to be about the thickness for standard .308 (not armor piercing). To have true ballistic armor, you are going to have to do some research and find plate rated for such use. A word of warning: It will be pricey.